These platforms include: OpenVZ, Cloud, Xen, VMWare, KVM and many other virtualisation options. Of these platforms, VMWare and Xen are the most recognizable and most used.
VMWare, being the oldest of the two, is more established with a wider user base and more dedicated user support system. Having a better dedicated user support means that with VMWare, users are more likely to have their technical issues handled faster and more efficiently as compared to users of Xen.
Price wise, VMWare is more expensive as compared to Xen. This pricing difference is more or less the same with Xen when you consider that VMWare has a higher capability to support simultaneous running of more virtual machines (than Xen) bearing the same specifications.
VMWare is faster than Xen. VMWare uses binary emulation and translation to communicate with the hardware of the host operating system. On the other hand, Xen uses paravirtualization where, for it to offer virtualization, it has to modify the base operating system such that the instructions from the virtual machine are sent directly to the hardware. As such, this difference in operation makes VMWare to be more faster, easier to install and operate when compared Xen.
Xen requires specific hardware type to operate, AMD-V or Intel-VT. This implies that individuals who have hardware that is incompartible, no matter how powerful it is, will have to incurr extra cost of upgrading for them to use the system. This is not the case with VMWare. The VMWare is capable of running on any hardware provided that it meets the minimum requirements. This means that the VMWare is compartible with majority of hardware and that users do not have to incur any extra cost for them to use it.